Patients with the diffuse forms of systmic lupus erythematosus nephritis were invited to enter a therapeutic trial. The three programs were corticosteroids only; corticosteroids with cyclophosphamide and azathioprine, both in low doses; and corticosteroids with intermittent intravenous cyclophosphamide. Regular follow-up of the patients admitted continues. Long-term studies of patients in our earlier trials suggest that the degree of chronicity on the renal biopsy may provide important prognostic information. The subject of patients with moderate chronicity responds to oral azathioprine or oral cyclophosphamide when added to low doses of corticosteroids.